50s Hemi Engine Build With 21st Century Technology - A Contemporary Chrysler - Tech

Returning to my old stomping ground, I coaxed Bill Jenks at Mooneyes to grind me a cam for the 331. Using a 354-style blank, Bill ground a 0.461-inch lift 280-degree solid lifter cam that'll make the old Chrysler run like a watch with power to spare. A set of solid lifters from a 318 Chrysler was provided from Egge to fit the Hemi.

Speed-O-Motive recommended using CMW Entech assembly lube for the entire assembly, including the cam and lifters. Rotella heavy-duty oil has been used as well and will be used in the engine to help break in the assembly as many modern motor oils lack the appropriate properties necessary for the old flat tappet motors.

I made a cam installation tool by welding a bolt to a piece of tubing. Care must be taken when installing the cam to not knick the bearing surfaces.

This ring faces with the chamfer pointed towards the back of the block and supports the cam timing gear.

A thrust plate bolts to the front of the block and controls fore and aft cam movement behind the timing chain assembly. The cam retaining bolt and washer are indexed to fit over the keyway of the cam. Note the relationship of the dots on the crank and cam timing gears. While some engine builders recommend degreeing the cam, Bill Jenks mentioned that since the cam was reground on a machine that registered everything off the keyway, there's no chance of the lobes being off time. Fifty years experience can't be wrong.

With the cam installed, the lifters and pushrods were dropped in and it was time to start adjusting the valves. The 331 is running adjustable pushrods from Hot Heads to set the valve lash.

A timely and frustrating dance to say the least, the valves need to be properly adjusted with the recommended 0.015-inch valve lash, measured here with a feeler gauge.

With the head installed, torqued, and the No. 1 cylinder valves adjusted, everything was pulled apart to measure piston to valve clearance. A tedious procedure, it's easier than finding out too late that the clearance isn't within the recommended 0.100-inch. Modeling clay was applied to the valve area of the piston and the depth measured with a caliper after the engine was turned over a few revolutions.

With the clearances checking out, the heads were reassembled, torqued, and the valves readjusted.